textproduct: Albany

SYNOPSIS

Dry conditions through Tuesday morning will give way to widespread, nuisance rainfall Tuesday afternoon through Wednesday morning courtesy of the passage of an upper-level disturbance. Temperatures surge above normal Wednesday as light showers linger in response to a passing warm front. A potent cold front then swiftly tracks through the region Wednesday evening or Wednesday night, causing temperatures to nose-dive below normal and significant lake effect to develop Thursday into Saturday morning. Drier conditions are expected Saturday afternoon into Saturday night before another storm system threatens potentially widespread precipitation to end the weekend.

SHORT TERM /THROUGH WEDNESDAY NIGHT/

Dry conditions will remain in place tonight and into tomorrow morning as the anticyclone drifts east and begins to exit the region. A few hours of radiational cooling tonight will see temperatures drop widely into the 20s to near 30, but lows will likely be reached before or around midnight as clouds begin to lower ahead of an approaching upper-level shortwave and surface trough. By tomorrow afternoon, an area of light, stratiform rain will begin to overspread the region from southwest to northeast as warm air advection and isentropic lift increase ahead of a warm front associated with a developing area of low pressure along the surface wave. Highs tomorrow will reach the 40s to low 50s with pockets of upper 30s across the highest elevations of the Southwest Adirondacks and Southern Greens.

Lows Tuesday will be on the mild side due to rain and ample cloud coverage with values in the 30s to low 40s. Rain from Tuesday night tapers off Wednesday morning as the stratiform rain shield departs to the northeast. Scattered showers will remain in the wake of the stratiform rain shield as the aforementioned warm front lifts northward, but a brief break is anticipated later in the afternoon within the pseudo-warm sector of the primary surface low that will be entering the Great Lakes by Wednesday afternoon beneath a closed low aloft. Courtesy of the warm- advected environment and this pseudo- warm sector, highs Wednesday will surge into the upper 40s to near 60 with pockets of mid 40s across higher terrain regions and low 60s in the lower Mid- Hudson Valley.

The warm up Wednesday will not be long lived as the primary low and its upper-level counterpart deepen on their northeast track into southwest Quebec and a potent cold front subsequently rotates through the region. Some additional rain showers, and perhaps a rumble of thunder, will pulse through the region along and ahead of the front through Wednesday night, with snow beginning to mix in at the higher elevations of the Southwest Adirondacks. Lows Wednesday will fall to the mid 20s to low 30s with most shower activity tapering off by early Thursday morning.

LONG TERM /THURSDAY THROUGH MONDAY/

Key Messages:

- Medium to high confidence in warning-level snowfall accumulations (40 to 70% of >7" over 72 hours) resulting from upslope and lake effect snowbands across northern Herkimer County Thursday afternoon through Friday night.

- Medium to high confidence in advisory-level snowfall accumulations (40 to nearly 100% of >4" over 72 hours) resulting from upslope and lake effect snowbands across portions of the Southwest Adirondacks and western Mohawk Valley Thursday afternoon through Friday night.

- Low to medium confidence in advisory-level wind gusts (20-60% >45 mph) across portions of the Southwest Adirondacks, Lake George Region, Mohawk Valley, Eastern Catskills, Southern Greens, Berkshires, and Taconics Thursday and Friday.

Discussion: Persistent deepening of the upper-level low as it drifts northward Thursday through Thursday night will enhance cyclonic vorticity advection as potent cold air advection continues in the wake of the cold front. As such, lake effect and upslope snow will develop across the Southwest Adirondacks late Thursday afternoon/early Thursday evening. Southwest flow to start will allow lake effect bands to primarily become situated across far northwest Herkimer and possibly Hamilton Counties, with orographic enhancement leading to potentially heavier snowfall rates. As an embedded shortwave pulses through the mean flow of the upper-level trough, extending southward from the base of the upper low, winds will gradually veer from the southwest to the west Friday, possibly even becoming more northwesterly by Friday night such that snowbands begin to wobble southward and extend through the western Mohawk Valley and into portions of the Northeast Catskills. Orographic enhancement will continue, leading to light to moderate accumulations in the western Mohawk Valley and portions of the Eastern Catskills, aligning with strong low- level winds to give way to the development of upslope snow showers in the Southern Greens and the extension of snow bands as far south and east as the Capital District and possibly even the Berkshires through Saturday morning. High pressure will then begin to build in across the region from the southwest Saturday, pairing with flat ridging aloft to cut off lake effect from increased subsidence.

When all is said and done, storm total snowfall accumulations are anticipated to be greatest in the Southwest Adirondacks where values ranging anywhere from 2 to 10 inches are possible. However, light accumulations are also possible with the northeast Catskills, western Mohawk Valley, and Southern Greens. Based on the latest 13z run of the NBM, we have medium to high confidence (40 to 70%) in at least 7 inches of snow mainly across northern Herkimer County. However, there's also medium to high confidence (40 to nearly 100%) in at least 4 inches of snow across all of the Southwest Adirondacks and western Mohawk Valley. Therefore, in collaboration with neighboring offices and with the greatest confidence in moderate to heavy snowfall resulting from lake effect snow bands, along with orographic enhancement, we have issued a Winter Storm Watch for all of Herkimer County. Should confidence increase in at least 7 inches of snow in Hamilton County, the Watch could be expanded in future forecast iterations. It is also important to note that the strong cold advection along with the steep pressure gradient will make for gusty conditions Thursday and Friday. In fact, there's a 20 to 60% chance for wind gusts to exceed 45 mph, per the latest LREF, across portions of the Southwest Adirondacks, Lake George Region, Mohawk Valley, Eastern Catskills, Southern Greens, Berkshires, and Taconics. Therefore, not only will Wind Advisories possibly be needed, but blowing snow will be a concern. Blowing snow paired with heavy snowfall rates will pose a significant hindrance to visibility, potentially significantly impacting travel for the Thanksgiving holiday and the Friday morning and evening commutes. We will be monitoring this element of the forecast closely and messaging appropriately for holiday travel preparations.

With high pressure in place Saturday, dry conditions will be reinforced regionwide and linger into at least part of the night Saturday night. However, another storm system threatens the return of widespread precipitation for the end of the weekend and possibly into the beginning of the work week next week. There is a lot of uncertainty pertaining to this system at this lead time, however, so we did not deviate from the latest NBM solution.

Temperatures throughout the long term period will be below normal for the most part after the passage of the aforementioned cold front. Highs Thursday will be the warmest with values in the upper 20s to low 40s. Friday and Saturday's highs will be fairly similar with mid 20s to near 40. Sunday's values will then be similar to, though a few degrees cooler than, Thursday. Lows throughout the period will largely be in the upper 10s to 20s.

AVIATION /00Z TUESDAY THROUGH SATURDAY/

Through 00z Wednesday...Increasing cirrus canopy expected tonight with VFR conditions prevailing at ALB and POU. Some intermittent MVFR vis from patchy fog cannot be ruled out at GFL between 03 - 07 UTC before clouds lower/thicken enough to reduce the chance for fog. Not enough confidence to include MVFR vis at PSF but will monitor trends. If temperatures drop enough this evening before cloud coverage increases, we may need to add an amendment.

Clouds continue to lower and thicken through the morning into the early afternoon hours before cigs drop to 2500-3500 ft as rain showers arrives from southwest to northeast by 20 - 22 UTC. Rain turns steady shortly after arriving and likely leads to MVFR vis towards the end of the TAF period for ALB, PSF, and POU. Otherwise, light and variable winds tonight become southerly tomorrow morning and increase to 5-8kts with gusts up to 15-20kts mainly at ALB and PSF.

Outlook...

Tuesday Night: High Operational Impact. Definite RA. Wednesday: Moderate Operational Impact. Chance of SHRA. Wednesday Night: Moderate Operational Impact. Breezy. Chance of SHRA. Thanksgiving Day: Moderate Operational Impact. Windy With Gusts To 34 kts. NO SIG WX. Thursday Night: Moderate Operational Impact. Breezy. Chance of SHSN. Friday: Moderate Operational Impact. Windy With Gusts To 37 kts. Chance of SHSN. Friday Night: Low Operational Impact. Breezy. Slight Chance of SHSN. Saturday: No Operational Impact. NO SIG WX.

ALY WATCHES/WARNINGS/ADVISORIES

CT...None. NY...Winter Storm Watch from Thursday afternoon through Saturday morning for NYZ032-038. MA...None. VT...None.